CVE-2021-27290 is a high-severity (CVSS 7.5) vulnerability in ssri. 2 public exploit references exist, so weaponization risk is real. A fix is available for ssri — see the affected versions and patch details below.
Regular Expression Denial of Service (ReDoS)
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-27290 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
ssrinpmDescription
ssri 5.2.2-8.0.0, fixed in 8.0.1, processes SRIs using a regular expression which is vulnerable to a denial of service. Malicious SRIs could take an extremely long time to process, leading to denial of service. This issue only affects consumers using the strict option.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ssri | ≥ 5.2.2&&< 6.0.2 | 6.0.2npm install ssri@6.0.2 |
| 📦npm | ssri | ≥ 7.0.0&&< 7.1.1 | 7.1.1npm install ssri@7.1.1 |
| 📦npm | ssri | ≥ 8.0.0&&< 8.0.1 | 8.0.1npm install ssri@8.0.1 |
Affected Products
graalvmoraclesinec infrastructure network servicessiemensssrissri_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ssri, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ssri to 6.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27290 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Whilst the OpenShift ServiceMesh (OSSM) servicemesh-grafana and servicemesh-prometheus include the vulnerable ssri library, the vulnerable "strict" option is not used. Similar to OSSM, OpenShift Container Platform (OCP), Red Hat Advance Cluster Management for Kubernetes (RHACM) and OpenShift distributed tracing…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | nodejs:12-8040020210708131418.522a0ee4 | RHSA-2021:3073 |
| Red Hat Enterprise Linux 8 | nodejs:14-8040020210708154809.522a0ee4 | RHSA-2021:3074 |
| Red Hat Enterprise Linux 8.1 Extended Update Support | nodejs:12-8010020210817113128.c27ad7f8 | RHSA-2021:3639 |
| Red Hat Enterprise Linux 8.2 Extended Update Support | nodejs:12-8020020210817125332.4cda2c84 | RHSA-2021:3638 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-nodejs12-nodejs-0:12.22.2-1.el7 | RHSA-2021:2931 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-nodejs14-nodejs-0:14.17.2-1.el7 | RHSA-2021:2932 |
Frequently Asked Questions
Is CVE-2021-27290 in your dependencies?
Find it across npm, including transitive dependencies.